Investigation continues into a fire that heavily damaged a home Thursday at 570 S. Washington St. in Constantine.

Constantine Fire Department personnel collaborated Friday with an investigator from the Michigan State Police Fire Investigation Unit. Authorities said the fire began in a bedroom, but they have not pinpointed a specific cause.

The incident is still under review by Constantine police.

Constantine firefighters arrived at the home around 7 p.m. Thursday, soon joined by two other departments. Three people were at home at the time of the blaze. No one was injured.

A portion of U.S. 131 was closed for several hours.

Update on Tuesday's fire: Investigators have determined that a fire Tuesday at Custer Apartments in Constantine was accidental. Authorities said new tenants were moving in and placed a box next to a stove, which was accidently turned on and eventually set the box on fire.